Railway traffic controlling apparatus



March 17, 1942. E. M. ALLEN ,2 5 6 RAILWAY TRAFFIC CONTROLLING APPARATUSI Filed Jan. 13, 1940 2 Sheets-Sheet 1 Conzmlledbg liaoli Circuit nexzin advance.

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March 17, 1942. E. M. ALLEN 8 RAILWAY TRAFFI IIC CONTROLLING APPARATUSvI Filed Jan. 13, 1940 2 Sheets-Sheet, 2

W v X UpJSeaond I 259mm? Up JSecond ZZSKUMJ v 2 50001212 I v A pbjbc'ana' Code LI T l LI L] L] m Approach m zlspmm I SZowC'adg n H H I1Fl FT Medium C'ode l INV ENTOR H115 ATTORNEY Patented Mar. 17, 1942OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Application January 13,1940, Serial No. 313,754

8 Claims.

My invention relates to railway traflic controlling apparatus, andparticularly to apparatus for a railway signal system using coded energyhaving cyclic patterns of the time code type.

In time code systems it has been proposed to use slow release relays orslow pick-up relays or a combination of both as the decoding means, suchrelays responding in dififerent combinations to the diiierent lengths ofthe on and oil periods of the different codes. In decoding relays forsuch systems inaccuracy of operation due to variations of voltage of thecurrent source and variations of the operating periods of the relays dueto changes in the resistances of the relay windings because of varyingambient temperature must be compensated as well as the presence of thecoded energy detected and the operativeness of the means used to providethe slow acting characteristics for the decoding relays checked.

Accordingly, an object of my invention is the provision of novel andimproved decoding means for signaling systems using coded energy of thetime code type.

Another object of my invention is the provior sion of novel and improvedmeans for signal systems of the type here involved wherewith a shortperiod present in each of the difierent codes serves to make availableenergy for operation of the decoding relays.

Still another object of my invention isthe provision of novel andimproved decoding means for signal systems of the time code type whichis substantially free from variations in its operation periods becauseof changes in temperature.

Again, an object of my invention is the provision of improved decodingapparatus for signal systems of the time code type wherein the presenceof the means used to provide the slow acting characteristics of thedecoding relays is checked.

Other objects and advantages of my invention as well as the above listedobjects I attain by providing two reactance devices in which energy isalternately stored and released to control slow pick-up decoding relays,such reactance devices being preferably either condensers or inductors.Energy is stored in a selected one of such reactance devices during theon period of each code cycle and this stored energy is discharged toenergize selected ones of a group of slow pick-up relays during the ofiperiod of each code cycle. Each of these decoding relays is providedwith a preselected slow pick-up period and this stored energy is usedduring the on period of each code cycle-to energize other relays of thegroup of slow pick-up relays according to the duration of the on periodof the particular code. The circuits are proportioned to charge thereactance devices quickly and to discharge the devices at apredetermined rate so that either device can be fully charged during theshortest code period used and either device can supply energy for thelongest code period used. When condensers are used as the reactancedevices, the condensers themselves if of the electrolytic type whichhave a negative temperature coeflicient of resistance serve tocompensate for variations in the pick-up time of the slow pick-up relaysdue to variations of the resistances of the relay windings caused bychanges in ambient temperature. If the reactance device is an inductorincluding a winding mounted on a magnetic core, then asymmetric unitssuch as the copper oxide rectifier unit are provided to compensate forthe variations in the pick-up time of the slow pick-up relays due tochanges in temperature, since a copper oxide rectifier unit ischaracterized by a decrease in resistance in its forward direction whenthe temperature increases. When reactance devices are used as asecondary source of power in which energyis stored by operation of acode following relay and the energy stored in such reactance devices isused to energize decoding relays, operation of the code following relayis assured and false energization of any of the decoding relays becauseof a failure of the code following relay is avoided. To detect thepresence of coded energy I provide a control relay having two windingsone winding of which is energized along with certain of the slow pick-uprelays by the energy stored in one of the reactance devices and theother of which windings is energized along with other ones of the slowpickup relays by the energy stored in the other reactance device. Theslow pick-up characteristics of the decoding relays I obtain byincluding a resistor in series with the winding of each of therespective relays which resistor can readily be proportioned to give thedesired pick-up period for the associated relay and the presence ofwhich resistor is checked because the energizing current for the relayflows through the resistor. The signal operating circuits and othercontrolling circuits are governed by the two-winding relay and the groupor series of slow pick-up relays according to the extent the slowpick-up relays are energized by the particular code.

I shall describe two forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a diagrammatic view showing oneform of apparatus embodying my invention when used with a four-blockfive-indication wayside signal system for railways. Fig. 2 is adiagrammatic view showing a second form of apparatus embodying myinvention when used with a four-block fiveindication wayside signalsystem for railways. Figs. 3 and 4 are views diagrammaticallyillustrating different time codes that may be used with the apparatus ofFigs. 1 and 2, respectively.

In each of the different views like reference characters designatesimilar parts.

It is to be understood, of course, that my invention is not limited to afour-block five-indication wayside signal system and this one use servesto illustrate the many places wher apparatus embodying the invention isuseful.

Referring to Fig. 1, the reference characters la and lb designate thetraffic rails of a stretch of railway over which traffic normally movesin the direction indicated by an arrow, and which rails are formed bythe usual insulated rail joints into consecutive track sections of whichsections only the one full section W-X and the adjoining ends of the twoadjacent sections are shown for the sake of simplicity.

Each track section is provided with a track circuit which comprisesmeans for supplying coded energy to the rails at one end of the sectionand a code following track relay connected with the rails adjacent theother end of the section for operation of the relay by such codedenergy, such coded energy having different cyclic patterns of the timecode type and which cyclic patterns are selected in accordance withdifferent traffic conditions.

The means for supplying coded energy to the track circuit for section WXincludes a battery KB and a relay XR together with traffic controlledcode transmitting circuits to be later described. At this point in thedescription it is sufiicient to say that when relay XR is picked upclosing front contacts 4 and 5, the two terminals of battery XB areconnected across the rails la and lb to supply current thereto and whenrelay XR is released opening front con- 1 tacts 4 and 5 and closing backcontacts 6 and I, the battery XB is disconnected from the rails and therails are short circuited. It follows that by operation of relay XR.according to a cyclic pattern consisting of a preselected period duringwhich the relay XR is picked up and a selected period during which therelay is released, direct current of a time code corresponding to thecyclic pattern at which relay KR is operated is supplied to the trackcircuit of section WX.

At the left-hand end of Fig. 1 there is shown a medium and clear. In thediagrams the on periods of a code are represented by the raised portionsof the curve and the off periods of a code are represented by thedepressed portions of the curve. Under the first or approach trafficcondition relay XR, for example, is operated in cycles during each ofwhich it is picked up for substantially .3 second and released forsubstantially .1 second, and the coded track circuit current has acyclic pattern consisting of an on period of .3 second and an off periodof .1 second. Under the second or approach-slow trafiic condition, relayXR is picked up for .1

second and released for .3 second each operation cycle and the trackcircuit current has a cyclic pattern consisting of an on period of .1second and an ofi period of .3 second. Under the third orapproach-medium tramc condition, relay XR is picked up .1 second andreleased .9 second each operation cycle and the cyclic pat tern for thetrack circuit current has an on" period of .1 second and an 01f periodof .9 second. Under the fourth or clear trafiic condition, relay X5. ispicked up .9 second and released .1 second each operation cycle and thecyclic pattern for the track circuit current has an on period of .9second and an off period of .1 second. As stated hereinbefore, relay WRis operated in a manner similar to relay XR to impress correspondingcyclic patterns on the current to the track circuit for the section nextin the rear of section WX. The circuit means by which relays XR and WEar operated in accordance with different traffic conditions to producethe time codes illustrated in Fig. 3 will appear as the specificationprogresses.

It is to be understood my invention is not limited to the cyclicpatterns illustrated in Fig. 3 either as to the relative or as to theabsolute durations of the on and off periods, and the relative as wellas the absolute durations of the "on and off periods can be selected asdesired within the operating limits of the associated decoding relays.The cyclic patterns illustrated in Fig. 3 are one selection that issatisfactory. It is to be observed that one or the other of the twoperiods of each of the four different cyclic patterns is relativelyshort and is of .1 second duration.

A code following track relay WTR is connected across the rails adjacentthe entrance end of section W-X for operation by the coded currentsupplied to the track circuit of that section. Relay WTR is a directcurrent neutral relay of the usual type and hence is energized andpicked up closing its front contacts 8 and 9 when current fiows in thetrack circuit during each on period and is released closing backcontacts I0 and l I when no current flows during the off period of eachcode cycle. In other words, code following relay WTR is operated in stepwith the "on and off periods of the cyclic pattern of the differentcodes impressed upon the track circuit current.

Operation of code following track relay WTR causes energy to bealternately stored in and discharged from each of two reactance devicesor condensers Cl and C2. With relay WTR released closing back contactHi, condenser Cl is connected with a source of direct current whoseterminals are indicated at B and C and condenser Cl is charged thecharge buildin up rapidly. When relay WTR is picked up closing frontcontact 8, condenser CI is disconnected from the current source andconnected with a relay energizing circuit to be later referred to andthe condenser discharges the energy stored therein through suchenergizing circuit at a rate governed by the time constant of thecircuit. When relay WTR. is picked up closing front contact 9, thecondenser C2 is connected with the current source and condenser 02 isquickly charged, and then when relay WTR is released closing backcontact H, the condenser C2 is discharged into another relay energizingcircuit to be later referred to, at a rate governed by the time constantof the circuit. The energizing circuits into which the condensers Cl andClare discharged include a check or control relay AH and a, group orseries of slow pick-up relays which in Fig. 1 comprise relays BI-I, ADand BD, relays BH and AD being controlled by the energizing circuitassociated with condenser C2 and relay BD being controlled by theenergizing circuit associated with condenser Ci.

Resistors RE, R2 and R3 are associated with relays Bi-I, AD and BD,respectively, by being interposed in series with the winding of therespective relay. Each of these resistors provides the desired pick-upperiod for the respective relay. As indicated in Fig. l, resistor R1 isproportioned to provide a .3 second pick-up period for relay BH andresistors R2 and R3 are proportioned to provide a .9 second pick-upperiod for relays AD and BD, respectively, such pick-up periods forrelays BH, AD and 13D being selected to agree with the time codesillustrated in Fig. 3.

The check or control relay AH is a two-winding-relay and relay AH aswell as the slow pickup relays EH, AD and B1) are all made slightly slowto release, the release period for relay AH being just suficient tobridge the intervals required for code following relay WTR to movebetween its front and back contacts, and the release periods of relaysBH, AD and BD being just sufficient to bridge the relatively short .1second period of the diiferent time codes.

The energizing circuit into which condenser Cl discharges can be tracedfrom the right-hand erminal of condenser Cl over front contact 8 ofrelay WTR, front contact 14 of relay AH when that relay is picked up,top winding 15 of relay AH in multiple with resistor R3 and winding l6of relay B1) to wire l7 and thence to the lefthand terminal of condenserCI. The energizing circuit into which condenser C2 is discharged can betraced from the right-hand terminal of condenser C2 over back contact llof relay WTR, three multiple paths to wire H and thence to the left-handterminal of condenser C2, the first path including lower winding iii ofrelay AH, the second path including resistor RI and winding 19 of relayBH and the third path including resistor R2 and winding 2| of relay AD.

A slow release relay ABD is preferably associated with the slow pick-uprelays AD and BD by being controlled by a circuit extending fromterminal 13 of the current source over either front contact 22 of relayAD or front contact 23 of relay BD, winding 26 of relay ABD, wire I! andto terminal C of the current source. Relay ABD is provided to avoidpossible signal flashing of the wayside signal whose operating circuitsare governed by the group of slow pick-up relays as will later appear,and relay ABD may not be needed.

Relay AH and the associated series of slow pick-up relays selectivelycontrol the operating circuits of a wayside signal WS which governstrafiic through section W-X. Signal WS may be any standard type ofwayside signal and as here shown it comprises two searchlight signalmechanisms SI and S2 mounted on a single mast. In accordance with thewell-known construction for searchlight signals, each mechanism SI andS2 includes a rotor 12 and a field winding I3 for operating three colorscreens G, R and Y in front of an illuminated lamp 25, the particularcolor screen positioned in front of the lamp being in accordance withthe polarity of the energization of field winding I3. When field winding[3 of a signal mechanism is deenergized, the rotor l2 of that mechanismis biased to a position where the red color screen R is moved in frontof the lamp and a red light is displayed, when field winding I3 isenergized by current of reverse polarity, the rotor I2 is operated tomove the yellow color screen Y in front of the lamp and a yellow lightis displayed and when winding I3 is energized by current of normalpolarity, rotor I 2 is operated to move the green color screen G infront of the lamp and a green light is displayed. As indicateddiagrammatically, the rotor 12 of each signal mechanism operates circuitcontrolling contacts in the usual manner for such searchlight signals.

A code transmitter CT is also included in the apparatus. Codetransmitter CT is preferably of the well-known motor driven type whichis provided with two contact members 26 and 21 each of which contactmembers is operated in a cyclic manner as long as current is supplied tothe motor element of the code transmitter. In the form of the inventiondisclosed in Fig. 1, code transmitter CT is arranged so that in thecyclic operation of contact member 25 it is up to engage a contact 28for .1 second and is down to engage a contact 29 for .3 second. In thecyclic operation of contact member 21 it is up to engage a contact 30for .1 second and is down to engage a contact 3| for .9 second eachcycle.

The code transmitter CT controls the operating circuits for relay WRassociated with the section next in the rear, each such circuit beingalso controlled by relay AH, the series of slow pick-up relays and thecontacts operated by the signal mechanisms Si and S2.

Since relay XR is controlled in a manner similar to relay WR, it followsthat relay XR is controlled by the code transmitter and the decodingrelays governed by the track circuit for the section next in advance.

It is believed that the operating circuits for signal WS as well as thecircuit for controlling relays WR and KR. can best be understood from adescription of the operation of the apparatus.

' In describing the operation of the apparatus of Fig. l, I shall firstassume a train occupies section WX shunting the track circuit andcausing track relay WTR. to be inactive with its back contacts l6 and I!closed. Under this traffic condition relay AH and all of the slowpick-up relays BI-I, AD and DB are released because they are energizedonly by current supplied from condensers Cl and 02. It is to be noted,however, that condenser CI is now connected across the current sourceand is fully charged. Relay ABD is also deenergized and released becauseboth relays AD and BD are released. The operating circuits for windingl3 of the mechanisms SI and S2 are now all open and each mechanism isbiased with its respective color screen R in front of the lamp so thatthe signal WS displays a red light over a red light to give a stopsignal indication. Relay WR is provided with a circuit comprisingterminal 13, contact 32-33 and contact 34-35 of mechanism SI both closedwhen the winding I3 of that mechanism is deenergized, wire 36, contact26-29 of code transmitter CT, wire 31, contact 38-39 and contact 4II-4Iof mechanism S2 both closed when its winding I3 is deenergized, wire 42,winding of relay WR and terminal C. Since contact 26-29 of the codetransmitter CT is open .1 second and closed .3 second each operationcycle of contact member 26, the relay WR is released .1 second andpicked up .3 second each such operation cycle so that the approach codeof Fig. 3 is impressed upon the track circuit current for the sectionnext in the rear as long as the train occupies section WX.

I shall next assume the train in section W-X advances to the right andoccupies the section next in advance of section WX. Relay XR which iscontrolled by the track circuit apparatus for the section next inadvance in the same manner relay WR is controlled by the track circuitapparatus of section WX is now operated to impress the approach codeupon the current of the track circuit of section W-X and code followingtrack relay WTR is correspondingly operated. The first time relay WTR ispicked up, the energy stored in condenser CI discharges into an opencircuit because front contact I4 of relay AH is now open and hence theenergy stored in condenser CI performs no useful function during thisfirst on period of the code. Condenser C2 is charged during this firston period due to the closing of front contact 9 of relay WTR. When relayWTR is released during the first .1 second off period, condenser CI isrecharged and condenser C2 discharges into its associated energizingcircuit and relay AH is picked up due to the energization of its lowerwinding I8. Neither slow pick-up relay BH nor AD, however, is picked upby the discharge from condenser C2 because the duration of the offperiod is only .1 second whereas the pick-up periods for relays BH andAD are .3 and .9 second, respectively. On the next on period of the codeand relay WTR is picked up, condenser CI discharges into its associatedenergizing circuit and relay AH is retained picked up due to theenergization of its top winding I5. Relay ED is not picked up by thedischarge of condenser CI, however, because the duration of the onperiod is only .3 second whereas the pickup period of relay ED is .9second. Consequently, relay AH is retained energized due to thealternate energization of its two windings as long as relay WTR isoperated in step with the approach code. and relay ABD, however, are alldeenergized. With only relay AH picked up, the winding I3 of mechanismSI is energized at reverse polarity by current flowing from terminal Bover front contact 43 of relay AH, back contact 44 of relay ABD, windingI3 of mechanism SI, back contact 45 of relay ABD, wire I! and toterminal C; and mechanism SI is operated to move its color screen Ybefore the lamp. Mechanism S2 remains deenergized displaying a red lightand hence signal WS now displays a yellow light over a red light to givean approach signal indication. The relay WR is now provided with acircuit comprising terminal B, contact 32-46 of mechanism SI closed whenthat mechanism is operated to display a yellow light, front contact 41of relay AH, contact 26-28 of code transmitter CT, wire 31, contact38-39 and contact 40-4I of mechanism S2, wire 42, winding of relay WRand terminal C. Since contact 26-28 of the code transmitter The seriesof slow pick-up relays is closed for .1 second and open for .3 secondeach operation cycle of contact member 26, relay WR is operatedaccordingly to impress the approachslow code of Fig. 3 on the current ofthe track circuit for the section next in the rear when section W-X isunoccupied and the section next in advance of section W-X is occupied.

I shall next assume that the train moves to the right out of the sectionnext in advance and cocupies the second section in advance of sectionW-X. Since relay XR is controlled in the same manner as relay WR, relayXR is now controlled to impress the approach-slow code upon the currentof the track circuit for section W-X and relay WTR is correspondinglyoperated. When relay WTR is released during the off period of theapproach-slow code, condenser C2 discharges to energize winding I8 ofrelay AH and to energize winding I9 of relay BH to pick up that relaybecause the duration of the 01f period is .3 second which is the same asthe pick-up period of relay BH. Relay AD whose pick-up period is .9second is not energized for a period sufficient to be picked up andremains released. During the .1 second on period of the code condenserCI discharges to energize winding I5 of relay AH retaining that relaypicked up. Relay BD whose pick-up period is .9 second remains releasedduring this short .1 second on period of the approach-slow code. Withrelays AH and BH both picked up closing front contacts 43 and 48,respectively, the winding I3 of each mechanism SI and S2 is energized atreverse polarity to cause each mechanism to operate its color screen Ybefore the respective lamp so that signal WS displays a yellow lightover a yellow light to give an approach-slow signal indication. Thecircuit for winding I3 of mechanism SI is the same as tracedhereinbefore, while the circuit for winding I3 of mechanism S2 extendsfrom terminal B over front contacts 43 and 48 of relays AH and BH,respectively, back contact 49 of relay BD, winding I3 of mechanism S2,back contact 50 of relay BD and to terminal C. Relay WR is now providedwith a circuit comprising terminal B, contact 32-46 of mechanism SI,front contact 4'! of relay AH, contact 21-30 of code transmitter CT,front contact 5| of relay BH, contact 40-52 of mechanism S2 closed whenthat mechanism displays a yellow light, wire 42, winding of relay WR andterminal C. Since contact 21-30 of the code transmitter is closed .1second and open .9 second each operation cycle of contact member 27, therelay WR is operated accordingly to impress the approach-medium code ofFig. 3 upon the current of the associated track circuit when twosections in advance of the associated section are unoccupied and thethird section in advance is occupied.

Assuming next that the train advances to the right another track sectionso that there are two unoccupied sections between section WX and thesection occupied by the train, the relay XR is operated to impress theapproach-medium code on the track circuit current for section WX. Duringthe off period of this code, condenser C2 discharges into the associatedenergizing circuit and relays AH, BH and AD are all picked up becausethe duration of the 01f period of the code is .9 second. During the .1second on period of this code, condenser CI discharges into itsassociated energizing circuit and retains relay AH picked up, but relayBD remains released. With relay AD picked up closing front contact 22,relay ABD is picked up closing its front contacts 53 and 54 to polechange the circuit for winding I 3 of mechanism .SI so that mechanism SIis energized at normal polarity to move the color screen G in front ofthe lamp. The winding I3 of mechanism S2 is energized at reversepolarity over a circuit the same as previously described except frontcontact 57 of relay ABD is in multiple with front contact 48 of relayBH. Consequently,

signal WS now displays a green light over a yellow light to give anapproach-medium signal indication. Relay WR is now provided with acircuit comprising terminal B, contacts 3233 and 34-26 closed when themechanism SI is operated to display a green light, front contact I2 ofrelay ABD, contact 2'l3l of code transmitter CT, front contact 5! ofrelay EH, contact it-52 of mechanism S2, wire 52, winding of relay WRand terminal G. Since contact 2?3I of code transmitter CT is closed .9second and open .1 second each operation cycle oi contact member 21,relay WR is correspondingly operated to impress the clear code of Fig. 3upon the current of t -e associated track circuit when there are threeunoccupied sections in advance of the associated track section. 7

Assuming the train moves another section to the right so that there arethree unoccupied sections between the section occupied by the train andsection WX, the relay XR which is operated similar to relay WR is nowoperated to period of this code, condenser C2 discharges into theassociated energizing circuit for .l second and relay AH is retainedenergized, but neither relay BH nor AD is energized for a suificientperiod to I on period is-.9 second which is the same as the pick-upperiod of relay BD. Relay ABD is now picked up over front contact 23 ofrelay BD. Under this combination of the relays, winding I3 of mechanismS! is energized at normal polarity the same as before. When relay ED ispicked up closing front contacts and 56, the circuit for winding 13 ofmechanism S2 is pole changed and that winding is energized at normalpolarity. Since both signal mechanisms S5 and S2 are now energized atnormal polarity, signal WS displays a green light over a green light togive a clear signal indication. Relay WR is provided with a circuitcomprising terminal B, contacts 3233 and 3 l2 3 of mechanism SI, frontcontact I2 of relay ABD, con act ET-SI of code transmitter CT, frontcontact 58 of relay BD, contacts 38-459 and itii of mechanism S2, wire:32, winding of relay WR and terminal C. Consequently, relay WR is stilloperated to impress the clear code upon the current of the associatedtrack circuit.

Among the advantages of the apparatus of Fig. l is the assurance ofoperation of the code following track relay since energy used forenergizing the decoding relays is obtained by the storage of energy ineither the condenser CI or C2 over contacts of the code following relayclosed during a selected one of the on and off periods of the code, andthe discharge of such stored energy to the decoding relays over contactsof the code the code. When condensersCI and C2 are of t-he electrolytictype, the negative temperature coefficient of such condensers willautomatically compensate for the increase in the resistance of thewindings of the slow pick-up relays caused.

bysuch increase in temperature. Thus a substantially uniform pick-upperiod for each decoding relay irrespective of changes in temperature Inthe form of the invention disclosed in Fig. 2,

the apparatus is similar to that of Fig. 1 and the apparatus of Fig. 2will be described only in the manner whereinit difiers from theapparatus of Fig. 1. The track circuitfor section WX of Fig. 2 isprovided with a code following track relay WTRI- which differs fromtrack relay WTR of Fig. 1 in that relay WTRI isprovided with two setsfofthe well-known continuity transfer type of contact. The preselectedcyclic patterns for the different codes for the apparatus of Fig. 2differ from the cyclic patterns used with the apparatus of Fig. 1 bothin the relative and absolute durations of the on and off periods. Thecyclic patterns for the. different codes'used with the apparatus of Fig.2 will be apparent from an inspection of Fig. 4 when considered with theexplanation of the cyclic patterns illustrated for the codes in Fig. 3.The reactance devices of Fig. 2 are indicated at MI and M2 and eachdevice includes a winding mounted on a magnetic I core, the device MIincluding a winding BI and the device M2 including a winding BI. Whenrelay W'I'RI is released closing back contact 62-63, winding 6d ofdevice-MI is connected with the B and C terminals of the current sourceand current flows in winding 69 to store energy in the magnetic core ofdevice MI. When relay WTRI is picked up closing front contact 63-454,the winding 6% of device MI is disconnected from the current source andis connected to an energizing circuit to be later referred to and themagnetic energy stored in the magnetic core of device MI decays toinduce an electromotive force in winding 6! which causes current to flowin such energizing circuit. In like manner when relay WTRI is picked upclosing front contact 65-65,'the winding [SI of device M2 is connectedwith the B and C terminals of the current source and current flows inwinding BI causing magnetic energy to be stored in the magnetic core ofdevice M2, and when relay WTRI is released closing back contact 655 I,winding tI. is disconnected from the current source and connected to anenergizing circuit to be shortly described and current flows in suchcircuit due to the dying away of the magnetic energy.

The energizing circuits associated with windings 6i) and SI of devicesMI and M2 control the check relay AH and the series of slow pick-uprelays BH, AD and BD all of which relays are similar to those of Fig. 1.To be explicit the energizing circuit supplied with current fromreactance device MI can be traced from the lefthand terminal of windingt0 over wire I'I, winding I5 of relay AH in multiple with resistor R6and winding I6 of relay BD, front contact I4 of following relay closedduring the other period of relay AH when closed, an asymmetric unit 68preferably of the copper oxide rectifier type, front contact 6364 ofrelay WTRI and to the righthand terminal of winding 60. The energizingcircuit supplied with current from reactance device MZ can be tracedfrom the left-hand terminal of winding 6| over wire i1, three multiplepaths one including winding E8 of relay AH, a second one includingresistor R4, winding 19 of relay BH and front. contact I of relay AH,and the third path including resistor R5, winding 2| of relay AD, frontcontact ll of relay BH and front contact 10 of relay AH, and thenthrough an asymmetric unit 69 also preferably of the copper oxiderectifier type, back contact 66-61 of relay WTRI and to the right-handterminal of winding 6|. It should be observed that the path includingwinding 2! of relay AD is completed over front contact H of the relay BHand the front contact 10 of relay AH and the path including winding I9of relay BH includes the front contact 10 of relay AH.

To agree with the cyclic pattern illustrated in Fig. 4, resistor R4 isproportioned to give relay BH a .2 second pick-up period and resistors Rand R6 are proportioned to give slow pick-up periods of 1.2 secondsforrelays AD and BD, respectively.

In Fig. 2, the operating circuits for signal mechanisms SI and S2 ofwayside signal WS and the circuits for controlling relay WE aresubstantially the same as in Fig. l.

The operation of the apparatus of Fig. 2 will be apparent from aninspection of Fig. 2 when considered with the description of theoperation of the apparatus of Fig. 1 and it is suflicient to describethe operation of theapparatus of Fig. 2 only briefly to point out theresults accomplished under the several different trafiic conditions.When a train occupies section WX and track 'relay WTRI is inactive,relay AH and the series of associated slow pick-up relays are allreleased so that the winding 13 of each signal mechanism SI and S2 isdeenergized and the signal WS displays a stop signal indication. RelayWR associated with the track circuit for the section next in the rear isprovided with a circuit including terminal B, contacts 32'33 and 34-35of mechanism SI, contact 25-29 of code transmitter CT, contacts 3839 and4B4l of mechanism S2, winding of relay WR and terminal C, andconsequently relay WR is operated to impress the approach code of Fig. 4upon the track circuit current of the associated section as long assection W- X is occupied because contact 2629 is closed .2 second and isopen .1 second each code cycle of contact member 26 of the codetransmitter.

When the train moves from section W-X of Fig. 2 to the right to clearthat section and occupy the section next in advance, relay XR isoperated to effect the approach code upon the current of the trackcircuit of section WX and track relay WTRI is correspondingly operated.The first time relay WTRI is picked up, the energy stored in device MIeffects no useful purpose because the associated energizing circuit isopen at front contact I4 of relay AH, but energy is stored in device M2.On the first off period of the code and relay WTR! is released, energyis again stored in device MI and the energy stored indevice M2 isapplied to its associated energizing circuit and relay AH is picked up,but neither relay BH nor AD is picked up because the duration of the offpower is only .1 second whereas the pick-up periods for the relays ADand BH are .2 second and 1.2 seconds, respectively.

On the next on period of the code, the winding l5 of relay AH isenergized to retain that relay picked up due to the current created bythe dying away of the magnetic energy stored in device Ml, but relay EDis not picked up because the duration of the on period is .2 secondwhereas the pick-up period of relay ED is 1.2 seconds. It follows thatrelay AH is retained picked up by the alternate energizing of itswindings as long as relay WTRI is operated at the approach code. Withrelay AH picked up closing front contact 43, the winding l3 of mechanismSI is energized at reverse polarity and mechanism S2 is deenergized andsignal WS displays an approach signal indication. Relay WR is nowcontrolled over a circuit which includes terminal B, contact 32-46 ofmechanism SI, front contact 31 of relay AH, contact 26-28 of codetransmitter CT and then as previously traced. Hence relay WR is operatedto impress the approach-slow code of Fig. 4 on the track circuit of theassociated section when the section next in advance is unoccupied andthe second section is occupied, because contact 26-28 is closed .1second and is open .2 second each operating cycle of contact member 26.

When the train advances another section to the right so that there isone unoccupied section between section WX and the section occupied bythe train, relay XR is operated to impress the approach-slow code on thetrack circuit current of section WX and code following relay W'TRI iscorrespondingly operated. Relays AH and BH are now picked up, relay AHbeing picked up due to the alternate energization of its two windingsand relay BH being picked up because the duration of the off period ofthe code is .2 second and the current created by reactance device M2continues to flow in the winding of relay IBH for the full pick-upperiod of that relay. With relays AH and BH picked up closing frontcontacts 43 and 48, the winding I 3 of each mechanism SI and S2 isenergized at reverse polarity and signal WS displays an approach-slowsignal indication. Relay WR is now provided with a circuit thatcomprises terminal B, contact 32-46 of mechanism SI, front contact 41 ofrelay AH, contact 2130 of code transmitter CT, front contact 5| of relayBH, contact 4ll--52 of mechanism S2 and as previously traced. Hencerelay WR is operating to impress the approach-medium code of Fig. 4 onthe current of the associated track circuit in response to two sectionsin advance being unoccupied and the third section in advance beingoccupied.

When the train moves another section to the right and there are twounoccupied sections between section WX and the section occupied by thetrain and relay XR is operating to impress the approach-medium code onthe current of the track circuit of section WX, relays AH, BH and AD areall picked up. Relay A-H is picked up as before and both relays BH andAD are picked up because the duration of the off period is 1.2 seconds.Relay ABD is now picked up over front contact 22 of relay AD and polechanges the circuit for winding is of mechanism SI so that signal WS nowdisplays an approach-medium signal indication. The circuit for relay WRcomprises terminal B, contacts 3233 and lid-20 of mechanism Si, frontcontact 12 of relay ABD, contact 2l3l of code transmitter CT and aspreviously traced, and relay WR is operated to impress the clear code onthe current of the associated track circuit in response to threesections in advance being unoccupied.

With the train moving another section to the right so that there arethree unoccupied sections between section WX and the section occupied bythe train and relay XR. is operated to impress the clear code on thecurrent of track section WX, relays AH and BD are picked up. Relay AH ispicked up as previously described and relay ED is picked up due to the1.2 seconds on period of the code. Relays BH and AD are now releasedbecause the .1 second on period of the code is insuflicient to pick upthese relays. Relay ABD is now energized over front contact 23 of relayBD, and with relays AH, BD and ABD picked up, the signal WS is operatedto display the clear signal indication. The circuit for relay WR nowincludes terminal B, contacts 32--33 and 342i! of mechanism Si, frontcontact 72, contact 2'l-3l of code transmitter CT, front contact 58 ofrelay BD and thence as previously traced and relay WR is still operatedto impress the clear code on the current of the associated trackcircuit.

It is apparent that the apparatus of Fig. 2 possesses the sameadvantages as the apparatus of Fig. 1. In this connection, it is pointedout that the asymmetric units 68 and 69 are interposed in theirrespective circuits so as to pass current produced by the energy storedin the associated reactance device and to block the flow of any currentin the energizing circuit from the source of direct current. Also whenunits 58 and 69 are of the copper oxide rectifier type, the decrease inresistance in the forward direction of the unit when the temperatureincreases automatically acts to compensate for the increase in theresistance of the windings of the associated slow pick-up relays due tosuch increased temperature. Furthermore, by proper proportioning ofdevices Ml and M2 so that magnetic saturation is effected, asubstantially uniform voltage is applied to the respective energizingcircuit notwithstanding variations in the voltageof the charging source.

It is to be observed that apparatus embodying my invention can beapplied to track circuits using coded alternating current as well ascoded direct current. Also the apparatus can be used with train carriedapparatus of a railway cab signal system employing time codes of thetype involved.

While the invention has been described in connection with a four-blockfive-indication wayside signal system, it is apparent that the method ofcoding and decoding may be applied to apparatus providing a greater or alesser number of signal indications if desired.

In connection with the codes here used, it is to be observed that the .1second period of each code is not used to selectively pick up anycorresponding decoding relays, but rather is used to energize the checkrelay AH and keep the energizing circuits for the series of decodingrelays active to guarantee the presence of the code. It is furtherutilized in effecting the most restrictive proceed indication, namely,the approach signal indication. Furthermore, this .1 second period ofeach code is used as an interval in which to store energy in one or theother of the two reactance devices.

In wayside signal systems for railways, it is necessary to at timesprovide a special control for highway crossing signals. In code systemsof the type here involved it has been proposed to provide such specialcontrol for highway crossing signals by applying at times to the controltrack circuit for such highway crossing signals noncoded or steadyenergy. Such non-coded energy picks up the code following track relayand retains it steadily picked up to stop the warning operation of thehighway crossing signal, but the code following track relay whensteadily picked up still causes the wayside railway signal to remain atits stop position. Since in the apparatus embodying my invention as heredisclosed operation of the code following track relay is required toretain picked up the check relay and any of the decoding relays, andsince the check relay AH can be picked up at the start of any code onlyafter the code following track relay has first been picked up and thenreleased, it is obvious that steady or non-coded energy can be appliedto a track circuit at a highway crossing location to retain the codefollowing track relay steadily picked up to clear out or discontinue thewarning operation of the highway crossing signal when the rear of atrain passes over the highway and vacates the approach track section tothe highway crossing without changing the stop indication of the waysidesignal located at the entrance of such track section.

Although I have herein shown and described only two forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my inven tion.

Having thus described my invention, what I claim is:

1. In signaling apparatus for use with a signal system having atransmitting circuit supplied with coded energy of anyone of a pluralityof diiierent time codes each of which codes consists of a distinctivecyclic pattern which pattern is made up of an on and an off period withthe ofi period of each code of a distinctive preselected duration and towhich circuit is con nected a code following relay for operation thereofin step with the on and off periods of such time codes, the combinationcomprising, a reactance device, a circuit including a contact of saidcode following relay to connect a source of direct current with saidreactance device during the on period of each code cycle to store energyin said device, a series of relays, each of which is provided with adistinctive slow pick-up period, and another circuit including a contactof said code following relay to connect said reactance device with saidseries of relays during the off period of each code cycle to energizesaid series of relaysby said stored energy to pick up a number of therelays as determined by the duration of the off period of the particularcyclic pattern.

2. In signaling apparatus for use with a signal system having atransmitting circuit supplied with coded energy of any one of aplurality of diiierent times codes each of which codes consists of adistinctive cyclic pattern which pattern is made up of an on and an offperiod with the off period of each code or" a distinctive preselectedduration and to which circuit is connected a code following relay foroperation thereof in step with the on and of? periods of such timecodes, the combination. comprising, a reactance device, a circuitincluding a contact of said code following relay to connect a source ofdirect current with said reactance device during the on period of eachcode cycle to store energy in said device, a first and a second slowpick-up relay provided with different preselected slow pick up periods,and another circuit including a contact of said code following relay toconnect said reactance device to said slow pick-up relays during the offperiod of each code cycle to energize the slow pick-up relays by saidstored energy for selectively picking up such relays according to theduration of the off period of the particular cyclic pattern.

3. In signaling apparatus for use with a signal system having atransmitting circuit supplied with coded energy of any one of aplurality of different time codes each of which codes consists of adistinctive cyclic pattern which pattern is made up of an on and an offperiod each of a preselected duration and to which circuit is connecteda code following relay for operation thereof in step with the on and offperiods of such time codes, the combination comprising, a first and asecond reactance device each adaptable of storing energy, a firstcircuit including a contact of said code following relay to connect asource of direct current with said first reactance device during the offperiod of each code cycle to store energy in said first device, a secondcircuit including another contact of said code following relay toconnect a source of direct current with said second reactance deviceduring the on period of each code cycle to store energy in said seconddevice, a first and a second relay means each operable to difierentpositions according to the time interval the respective relay means isenergized, a first energizing circuit including a contact of said codefollowing relay to connect said first reactance device with said firstrelay means during the on period of each code cycle to energize thatrelay means by the energy stored in said first device for a timeinterval corresponding to the on period of the particular cyclicpattern, and a second energizing circuit including a contact of saidcode following relay to connect said second reactance device with saidsecond relay means during the off period of each code cycle to energizethat relay means for an interval corresponding to the off period of theparticular cyclic pattern.

4. In combination, a code following relay operable between two positionsin step with the on and off periods of coded energy of any one of aplurality of different time codes supplied thereto, an energy storingdevice capable of storing a predetermined amount of energy therein, afirst circuit including a contact of said code following relay closed ata selected one of its two positions to connect a source of directcurrent to said energy storing device, said first circuit proportionedto store energy rapidly and fully charge said energy storing device inthe shortest code period used in said different codes, anelectromagnetic means capable of operation to different positionsaccording to the duration said means is effectively energized, a secondcircuit including a contact of said code following relay closed at theother one of its two positions to connect said energy storing devicewith said electromagnetic means, and said second circuit proportioned todischarge the stored energy at a rate to effectively energize theelectromagnetic means for the longest code period used in said differentcodes.

5. In combination, a code following relay operable between two positionsin step with the on and off periodsof coded energy of any one of aplurality of different time codes supplied thereto, a condenser of apredetermined capacity, a first circuit including a contact of said codefollowing relay closed at a selected one of its two positions to connecta source of direct current to said condenser, said first circuitproportioned to fully charge said condenser in the shortest code periodused in said different codes, a series of slow pick-up relays whichrelays are provided with different preselected pick-up periods, and asecond circuit including a contact of said code following relay closedat the other one of its two positions to connect said condenser withsaid series of slow pick-up relays, said second circuit proportioned todischarge said condenser at a rate which effectively energizes eachrelay of said series of relays for the longest code period used in saiddifferent codes to pick up the slow pickup relays according to theparticular code operating said code following relay.

6. In combination, a code following relay operable between two positionsin step with the on and off periods of coded energy of any one of aplurality of different time codes supplied thereto, an inductor having awinding mounted on a magnetic core, a first circuit including a contactof said code following relay closed at a selected one of its twopositions to connect said inductor winding with a source of directcurrent, said first circuit proportioned to substantially magneticallysaturate said inductor core in the shortest code period used in saiddifferent codes, a series of slow pick-up relays which relays areprovided with different preselected pick-up periods, and a secondcircuit including a contact of said code following relay closed at theother one of its two positions to connect said inductor winding withsaid series of slow pick-up relays, said second circuit proportioned toeffectively energize each relay of said series of relays for the longestcode period used in said different codes by the current created by thedecay of the magnetic flux of said inductor core to pick up the slowpick-up relays according to the particular code operating said codefollowing relay.

7. In signaling apparatus for use with a signal system having atransmitting circuit supplied with coded energy of any one of aplurality of difierent time codes each of which codes consists of adistinctive cyclic pattern which pattern is made up of an on and an offperiod of a preselected duration and to which circuit a code followingrelay is connected for operation thereof in step with the on and offperiods of the particular code supplied, the combination comprising, afirst and a second reactance device, a first circuit including a contactof said code following relay to connect a source of direct current tosaid first reactance device during the off period to store energy insaid first device, a second circuit including a contact of said codefollowing relay to connect a source of direct current to said seconddevice during the on period to store energy in said second device, acheck relay having two windings, a first and a second decoding relayeach of which is provided with a distinctive slow pick-up period, athird circuit including a contact of the code following relay closedduring the ofi period to connect said second reactance device to onewinding of the check relay and to said first decoding relay to pick upby the energy stored in the second device the check relay and also thefirst decoding relay when the duration of the off period is at leastequal to the slow pick-up period of the first decoding relay, and afourth circuit including a contact of the code following relay closedduring the on period and a front contact of the check relay to connectsaid first reactance device to the other winding of the check relay andto said second decoding relay to retain by the energy stored in thefirst device the check relay picked up and to pick up the seconddecoding relay when the duration of the on period is at least equal tothe slow pick-up period of the second decoding relay.

8. In signaling apparatus for use with a signal system having atransmitting circuit supplied with coded energy of any one of aplurality of different time codes each of which codes consists of adistinctive cyclic pattern which pattern is made up of an on and an offperiod each of a preselected duration and to which circuit is connecteda code following relay for operation thereof in step with the on and offperiods, the combination comprising, a first and a second reactancedevice, a first circuit including a contact of said code following relayto connect a source of direct current to said first reactance deviceduring the off period to store energy in said first device, a secondcircuit including another contact of said code following relay toconnect a source of direct current to said second reactance deviceduring the on period to store energy in said second device, a checkrelay having two windings, a series of decoding relays each of whichrelays is provided with a slow pick-up period preselected to agree witheither the on or off period of a particular code, a third cir-' cuitincluding a contact of said code following relay closed during the oilperiod to connect said second reactance device to one winding of thecheck relay and certain ones of said decoding relays to pick up by theenergy stored in the second device the check relay and also suchdecoding relays Whose slow pick-up periods are not greater than theduration of the ofi period, and a fourth circuit including a contact ofthe code following relay closed at the on period and a front contact ofthe check relay to connect the first reactance device to theotherwinding of the check relay and to at least one other of the decodingrelays to retain by the energy stored in the first device the checkrelay picked up and to pick up the last mentioned decoding relay whenits slow pick-up period is not greater than the duration of the onperiod.

EARL M. ALLEN.

